Yesterday , I started in app purchase for our office new app. First time, It was crazy. I search on google and I found tutorial on [mobile.tutspulse.com ](http://mobile.tutsplus.com/tutorials/iphone/iphone-sdk-in-app-purchases/)but it's not full code and couldn't clear. How to test ? How to create sandbox ? I have many question after I read tutorial from [mobile.tutspulse.com](http://mobile.tutspulse.com). I tried step by step and it's not working. After that I found another one. It's from apple. [In App Purchase Programming Guide](http://developer.apple.com/library/ios/#documentation/NetworkingInternet/Conceptual/StoreKitGuide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40008267-CH1-SW1) . I understand most of the follow but there is no sample code in guide book. After I read guide from apple, I rewrote again and I got empy product list. I search again on google and I found [this](http://stackoverflow.com/questions/1780440/i-cannot-get-in-app-purchase-test-to-work). Stackoverflow answer is really useful. I found [In App Purchase Walk Through](http://troybrant.net/blog/2010/01/in-app-purchases-a-full-walkthrough/) Tutorial from stackoverflow. [http://troybrant.net/](http://troybrant.net/) tutorials is really great and he explain everything. All step are step by step. I met again the same problem. I received product list is empty. So, I deleted app from my device and try again. Finally, everything is working fine. Thank [troybrant.net](http://troybrant.net). It help me alot and I know to how to create test user and how to write code.